"As we extended our survey, samples were taken for later analysis of water chemistry, microbiology of soil and surfaces, and atmosphere for CO2 [carbon dioxide], temperature and humidity," team members added.
If anything, the astronauts can occasionally find themselves in more danger below the ground than they would above it. Indeed, ESA says it would likely take more time to extract astronauts from Sa Grutta in the event of an emergency than it would to get crewmembers home from the International Space Station.
To keep astronauts as healthy as possible, CAVES organizers stick to a schedule, choose food that isn't apt to spoil and plot the safest routes possible through the subsurface.
This year's crew also got several upgrades from previous expeditions to improve safety. These included new helmet lights, specially adapted shoes and a portable carbon dioxide monitor.
Science findings are still being analyzed, but NASA astronaut Mike Barratt did find some interesting carbon dioxide variations through the cave. Crewmembers also took several videos underground examining "the strong analogies between speleology and spaceflight," ESA officials added.